GALLIUM(III) ARSENIDE - (1303-00-0)

Introduction

Name: gallium(III) arsenide; gallium arsenide
* IUPAC
CAS Number: 1303-00-0
Chemical Formula: GaAs
Molar Mass: 144.6446 g
Mass Percent: Ga 48.202 %; As 51.797 % 

Classification

• inorganic

Uses/Function

• "A small amount of arsenic added to crystal gallium has resulted in a material (gallium arsenide or GaAs) that is particularly well adapted to many important semiconductor applications. Compared to the more common silicon semiconductors, GaAs displays relatively low sensitivity to heat, higher electron mobility, and the ability to withstand higher applied voltages. This means that GaAs transistors can be operated at higher frequencies and higher power with less associated noise.The nature of the band gap in GaAs also means that it is better at emitting light than silicon semiconductors, making it a material of choice for light-emitting diodes (LEDs). Though gallium is much more expensive than silicon, its high absorptivity allows for very thin films to be used as efficient collectors for solar cells. It has been used for this purpose in several Mars rovers. Challenges for the GaAs applications include its expense. Researchers are working on finding appropriate inexpensive substrates for growth of the GaAs wafers or films. In addition, arsenic is toxic and carcinogenic, so great care must be taken toward worker safety in the wafer-polishing process." 1

• "Gallium arsenide and gallium phosphide are used in a variety of semiconductor devices, including diodes and laser diodes, and may be found in computers and cell phones. Gallium arsenide is also used in solar batteries. Small amounts of gallium are found in thermometers, solders, arc lamps, batteries, and catalysts." 2

Bonding

Bonding: polar covalent
Ionic Character: 11.21 %

Thermochemistry

ΔHf° (s): -17 kcal/mol 3 = -71.13 kJ/mol
S° (s): 15.34 cal/(mol•K) 4 = 64.18 J/(mol•K)
ΔGf° (s): -16.2 kcal/mol 5 = -67.78 kJ/mol

For More Information

Sources

(1) - Halka, Monica and Nordstrom, Brian. Metals & Metalloids; Infobase Publishing: New York, NY, 2011; pp 27-28.
(2) - Halka, Monica and Nordstrom, Brian. Metals & Metalloids; Infobase Publishing: New York, NY, 2011; p 31.
(3) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(4) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(5) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.